HB2016 - List of Keywords (operation)

Paper	Title	Other Keywords	Page
MOAM4P40	A Fifteen Year Perspective on the Design and Performance of the SNS Accelerator	linac, injection, target, electron	9
	S.M. Cousineau ORNL, Oak Ridge, Tennessee, USA
	Commissioning of the Spallation Neutron Source accelerator began approximately fifteen years ago. Since this time, the accelerator has broken new technological ground with the operation of the world’s first superconducting H⁻ linac, the first liquid mercury target, and 1.4 MW of beam power. This talk will reflect on the issues and concerns that drove key decisions during the design phase, and will consider those decisions in the context of the actual performance of the accelerator. Noteworthy successes will be highlighted and lessons-learned will be discussed. Finally, a look forward toward the challenges associated with a higher power future at SNS will be presented.
	Slides MOAM4P40 [8.952 MB]
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MOAM5P50	LHC Run 2: Results and Challenges	luminosity, proton, ion, electron	14
	R. Bruce, G. Arduini, H. Bartosik, R. De Maria, M. Giovannozzi, G. Iadarola, J.M. Jowett, M. Lamont, A. Lechner, K.S.B. Li, D. Mirarchi, E. Métral, T. Pieloni, S. Redaelli, G. Rumolo, B. Salvant, R. Tomás, J. Wenninger CERN, Geneva, Switzerland
	The first proton run of the LHC was very successful and resulted in important physics discoveries. It was followed by a two-year shutdown where a large number of improvements were carried out. In 2015, the LHC was restarted and this second run aims at further exploring the physics of the standard model and beyond at an increased beam energy. This article gives a review of the performance achieved so far and the limitations encountered, as well as the future challenges for the CERN accelerators to maximize the data delivered to the LHC experiments in Run 2. Furthermore, the status of the 2016 LHC run and commissioning is discussed.
	Slides MOAM5P50 [9.283 MB]
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MOAM6P60	Recent Progress of J-PARC MR Beam Commissioning and Operation	injection, resonance, proton, kicker	21
	S. Igarashi KEK, Ibaraki, Japan
	The main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) has been providing 30-GeV proton beams for elementary particle and nuclear physics experiments since 2009. The beam power of 390 kW has been recently achieved with 2·10¹⁴ protons per pulse and the cycle time of 2.48 s for the neutrino oscillation experiment. Main efforts in the beam tuning are to minimize beam losses and to localize the losses at the collimator section. Recent improvements include the 2nd harmonic rf operation to reduce the space charge effect with a larger bunching factor and corrections of resonances near the operation setting of the betatron tune. Because the beam bunches were longer with the 2nd harmonic rf operation, the injection kicker system was improved to accommodate the long bunches. We plan to achieve the target beam power of 750 kW in 2018 by making the cycle time faster to 1.3 s with new power supplies of main magnets, rf upgrade and improvement of injection and extraction devices. The possibility of the beam power beyond 750 kW is being explored with new settings of the betatron tune.
	Slides MOAM6P60 [9.968 MB]
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MOPM4P01	Challenges and Performance of the C-ADS Injector System	rfq, linac, proton, cavity	36
	Y.L. Chi IHEP, Beijing, People's Republic of China
	Along with the rapid development of nuclear power plants in China, treatment of the nuclear waste has become a crucial issue. Supported by the "Strategic Priority Research Program" of the Chinese Academy of Sciences (CAS), The Chinese ADS project is now on-going based on the collaboration of several Chinese institutions. In the end of year 2015, China Initiative ADS (CIADS) program is approved by Chinese government, will construct in the Guangdong province south part of China. The proton accelerator of Chinese ADS is a superconducting CW linear accelerator. Its energy is 1.5GeV, with beam current of 10mA. Institute of High Energy Physics (IHEP) and Institute of Modern Physics (IMP) are responsible to developing this superconducting CW linear accelerator. In the injector part there are many challenges to developing several different low beta superconducting cavities and related hardware’s such like LLRF system etc. In this paper presents the progress of two different injector development including SC cavities and related hardware’s and performance test of two injectors and key hardware’s, and also brief introduction of CIADS program.
	Slides MOPM4P01 [3.751 MB]
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MOPL016	Effects of Energy Deposition Models and Conductive Cooling on Wire Scanner Thermal Load, Analytical and Finite Element Analysis Approach	radiation, linac, simulation, insertion	221
	B. Cheymol ESS, Lund, Sweden
	One of the main limitations of the wire scanner in high intensity linac is the inability of the wire to survive at high duty cycle. For the commissioning of such machines, duty cycle must be reduced to preserve interceptive devices. A good thermal model of the wire is needed to insure a safe operation of the wire scanner and set the limits of acceptable beam duty cycle. In this paper, we will discuss the influence of the energy deposition model and the efficiency of conductive cooling on the wire temperature, based on the ESS beam parameters.
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TUAM4X01	Electron Cloud in the CERN Accelerator Complex	emittance, electron, simulation, quadrupole	266
	G. Rumolo, H. Bartosik, E. Belli, G. Iadarola, K.S.B. Li, L. Mether, A. Romano CERN, Geneva, Switzerland M. Schenk EPFL, Lausanne, Switzerland
	Operation with closely spaced bunched beams causes the build up of an Electron Cloud (EC) in both the LHC and the two last synchrotrons of its injector chain (PS and SPS). Pressure rise and beam instabilities are observed at the PS during the last stage of preparation of the LHC beams. The SPS was affected by coherent and incoherent emittance growth along the LHC bunch train over many years, before scrubbing has finally suppressed the EC in a large fraction of the machine. When the LHC started regular operation with 50 ns beams in 2011, EC phenomena appeared in the arcs during the early phases, and in the interaction regions with two beams all along the run. Operation with 25 ns beams (late 2012 and 2015), which is nominal for LHC, has been hampered by EC induced high heat load in the cold arcs, bunch dependent emittance growth and degraded beam lifetime. Dedicated and parasitic machine scrubbing is presently the weapon used at the LHC to combat EC in this mode of operation. This talk summarises the EC experience in the CERN machines (PS, SPS, LHC) and highlight the dangers for future operation with more intense beams as well as the strategies to mitigate or suppress the effect.
	Slides TUAM4X01 [9.785 MB]
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TUPM1X01	Broadband Feedback System for Instability Damping in the SNS Ring	feedback, betatron, accumulation, extraction	288
	N.J. Evans ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy The transverse feedback system in the Accumulator Ring of the Spallation Neutron Source~(SNS) is intended to damp broadband (≈40-120~MHz), coherent betatron motion due to e-p interaction. The SNS feedback system is based on an analog delay-line model with some signal conditioning and tuning parameters implemented digitally. This system provides a simple setup with two primary knobs, phase and gain, as well as an equalizer. This simplicity comes at the cost of some flexibility normally found in a standard mode-by-mode design, namely mode-by-mode phase, and gain control. In this paper we discuss the design, tuning, evaluation, and operation of the SNS feedback damper, and discuss the tradeoffs implicit in the design of the system.
	Slides TUPM1X01 [2.352 MB]
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TUPM7X01	An Experimental Plan for 400 MeV H⁻ Stripping to Proton by Using Only Lasers in the J-PARC RCS	laser, proton, experiment, injection	310
	P.K. Saha, H. Harada, S. Kato, M. Kinsho JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie, I. Yamane KEK, Ibaraki, Japan
	The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC is gradually approaching to the design operation with 1 MW beam power. Studies are ongoing for further higher beam power of 1.5 MW. The injection and extraction energy of RCS is 0.4 and 3 GeV, respectively. Lifetime of the stripper foil is the highest concern beyond 1 MW beam power. We have also already started detail studies of H⁻ stripping to protons by using lasers. However, in order to avoid high magnetic field required in the process of laser-assisted H⁻ stripping to protons, especially for lower H⁻ energies, we are studying the possibilities of using only laser system for 400 MeV H⁻ beam in the RCS. The method is a three step process, similar to that of SNS but lasers are used instead of high field magnets in the 1st (H⁻ to H⁰) and 3rd step (H0* to p). A Nd:YAG laser can be properly used for both 1st and 3rd steps, where commercially available powerful Excimer laser will be used an H⁰ excitation in the 2nd step. Although detail R&D studies are necessary to reach to the ultimate goal, we plan to carry out an experiment in 2017. A detail of the present method, experimental schedule and the expected outcome will be presented.
	Slides TUPM7X01 [3.316 MB]
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TUPM3Y01	Operational Experience and Future Plans at ISIS	injection, acceleration, proton, simulation	333
	D.J. Adams STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom I.S.K. Gardner, B. Jones, A.H. Kershaw, A.P. Letchford, R.J. Mathieson, A. Pertica, B.G. Pine, A. Seville, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, 665 keV RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam transfer lines. The facility currently delivers ~2.8·10¹³ protons per pulse (ppp) at 50 Hz, which is shared between two target stations. High intensity performance and operation are dominated by the need to minimise and control beam loss, which is key to sustainable machine operation, allowing essential hands on maintenance. The facility has had several upgrades including an RFQ, ring Second Harmonic RF system, key developments of diagnostics and instrumentation required for improving beam control and a Second Target station. Upgrades being installed, or expected in the near future, include: a ring damping system, a new injector MEBT with fast injection chopper and an upgraded 50 Hz target. Operational experience of ISIS and the impacts of its past and future upgrades are discussed. Ideas for major upgrades to ISIS are briefly reviewed, as are the underlying R&D projects.
	Slides TUPM3Y01 [2.902 MB]
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THAM1X01	Reuse Recycler: High Intensity Proton Stacking at Fermilab	proton, electron, booster, vacuum	463
	P. Adamson Fermilab, Batavia, Illinois, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy. After a successful career as an antiproton storage and cooling ring, Recycler has been converted to a high intensity proton stacker for the Main Injector. We discuss the commissioning and operation of the Recycler in this new role, and the progress towards the 700 kW design goal.
	Slides THAM1X01 [1.978 MB]
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THAM2X01	The Operation Experience at KOMAC	target, linac, DTL, ion	468
	Y.-S. Cho, H.S. Kim, K. R. Kim, H.-J. Kwon, Y.G. Song Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea K.Y. Kim KAERI, Daejon, Republic of Korea
	Funding: This work was supported by the Ministry of Science, ICT & Future Planning of the Korean Government. A 100-MeV proton linac at the KOMAC (Korea Multi-purpose Accelerator Complex) is composed of a 50-keV microwave ion source, a 3-MeV four-vane-type RFQ, a 100-MeV DTL and 10 target stations for proton irradiation on samples from many application fields. The linac was commissioned in 2013 and the user service started in July 2013 with delivering proton beam to two target stations: one for a 20-MeV beam and the other for a 100-MeV beam. In 2015, the linac has been operated more than 2,800 hours with an availability of greater than 89%. The unscheduled downtime was about 73 hours, mainly due to problems of ion source arcing and failures of pulsed high-voltage power system. More than 2,100 samples from various fields such as materials science, bio-life and nano technology and nuclear science, were treated in 2015. Currently, a new target station for radioisotope production is under commissioning and a new target station for low-flux irradiation experiments is being installed. Operational experiences of the 100-MeV linac during the past 3 years will be presented in the workshop.
	Slides THAM2X01 [6.669 MB]
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THAM4X01	Investigation to Improve Efficiency and Availability in Control and Operation of Superconducting Cavity at ESS	cavity, klystron, LLRF, controls	474
	R. Zeng ESS, Lund, Sweden O. Troeng Lund University, Lund, Sweden
	The higher efficiency and higher availability (fault-tolerant oriented) of RF&Cavity system (with beam loading) to operate at, the more dynamic details needs to be identified, so as to have the abilities (a) to work at nonlinearities, (b) to work close to limitation, and (c) to change operation point quickly and correctly. Dynamic detail identifications rely heavily on high precision measuring and characterizing basic cavity parameters (Ql, R/Q, dynamic detuning, phase and amplitude) and system behaviours under beam-RF-cavity interactions. It is especially challenging to characterize these dynamics under varying operating points or environment. Advanced technologies in LLRF and ICS providing real time/online characterizing will be the key enablers for addressing such challenges. However, to be successful, the deployment of these technologies must be embedded within local conditions taking into account available resources, existing hardware/software structures and operation modes. Several improvement approaches will be introduced. For example, 15% or more energy efficiency improvement at ESS will be obtained by reduction of power overhead and optimization of operation.
	Slides THAM4X01 [2.165 MB]
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THAM4Y01	New Arrangement of Collimators of J-PARC Main Ring	collimation, beam-losses, proton, radiation	543
	M.J. Shirakata, S. Igarashi, K. Ishii, Y. Sato, J. Takano KEK, Ibaraki, Japan
	The beam collimation system of J-PARC main ring has been prepared in order to localize the beam loss into the specified area, especially during the injection period. At the first time, it was constructed as a scraper-catcher system in horizontal and vertical planes which consisted of one halo-scraper and two scattered protons catchers, whose the maximum beam loss capacity was designed to be 450W in the beam injection straight of the ring. In 2012, the scraper was replaced by two collimators with a movable L-type jaw for both planes. Two catchers remained at the same places, and they were used as collimators. This large change of design concept of main ring collimation system was required in order to increase the beam loss capacity more than 3kW. The system worked well but unexpected loss spots still remained in the following arc and straight sections. The four-axis collimator was developed with movable jaw in horizontal, vertical and skew configurations which has high cleaning efficiency. We have four four-axis collimators, two non-skew collimators, and one original catcher. The most effective arrangement of collimators was investigated in this report.
	Slides THAM4Y01 [2.426 MB]
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THAM5Y01	Path to Beam Loss Reduction in the SNS Linac Using Measurements, Simulation and Collimation	emittance, linac, optics, collimation	548
	A.V. Aleksandrov, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy. The SNS linac operation at its design average power currently is not limited by uncontrolled beam loss. However, further reduction of the beam loss remains an important aspect of the SNS linac tune up and operation. Even small “acceptable” beam loss leads to long term degradation of the accelerator equipment. The current state of model-based tuning at SNS leaves an unacceptably large residual beam loss level and has to be followed by an empirical, sometimes random, adjustment of many parameters to reduce the loss. This talk will discuss a set of coordinated efforts to develop tools for large dynamic range measurements, simulation and collimation in order to facilitate low loss linac tuning.
	Slides THAM5Y01 [7.186 MB]
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Paper

Title

Other Keywords

Page

MOAM4P40

A Fifteen Year Perspective on the Design and Performance of the SNS Accelerator

linac, injection, target, electron

9

S.M. Cousineau
ORNL, Oak Ridge, Tennessee, USA

Commissioning of the Spallation Neutron Source accelerator began approximately fifteen years ago. Since this time, the accelerator has broken new technological ground with the operation of the world’s first superconducting H⁻ linac, the first liquid mercury target, and 1.4 MW of beam power. This talk will reflect on the issues and concerns that drove key decisions during the design phase, and will consider those decisions in the context of the actual performance of the accelerator. Noteworthy successes will be highlighted and lessons-learned will be discussed. Finally, a look forward toward the challenges associated with a higher power future at SNS will be presented.

Slides MOAM4P40 [8.952 MB]

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MOAM5P50

LHC Run 2: Results and Challenges

luminosity, proton, ion, electron

14

R. Bruce, G. Arduini, H. Bartosik, R. De Maria, M. Giovannozzi, G. Iadarola, J.M. Jowett, M. Lamont, A. Lechner, K.S.B. Li, D. Mirarchi, E. Métral, T. Pieloni, S. Redaelli, G. Rumolo, B. Salvant, R. Tomás, J. Wenninger
CERN, Geneva, Switzerland

The first proton run of the LHC was very successful and resulted in important physics discoveries. It was followed by a two-year shutdown where a large number of improvements were carried out. In 2015, the LHC was restarted and this second run aims at further exploring the physics of the standard model and beyond at an increased beam energy. This article gives a review of the performance achieved so far and the limitations encountered, as well as the future challenges for the CERN accelerators to maximize the data delivered to the LHC experiments in Run 2. Furthermore, the status of the 2016 LHC run and commissioning is discussed.

Slides MOAM5P50 [9.283 MB]

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MOAM6P60

Recent Progress of J-PARC MR Beam Commissioning and Operation

injection, resonance, proton, kicker

21

S. Igarashi
KEK, Ibaraki, Japan

The main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC) has been providing 30-GeV proton beams for elementary particle and nuclear physics experiments since 2009. The beam power of 390 kW has been recently achieved with 2·10¹⁴ protons per pulse and the cycle time of 2.48 s for the neutrino oscillation experiment. Main efforts in the beam tuning are to minimize beam losses and to localize the losses at the collimator section. Recent improvements include the 2nd harmonic rf operation to reduce the space charge effect with a larger bunching factor and corrections of resonances near the operation setting of the betatron tune. Because the beam bunches were longer with the 2nd harmonic rf operation, the injection kicker system was improved to accommodate the long bunches. We plan to achieve the target beam power of 750 kW in 2018 by making the cycle time faster to 1.3 s with new power supplies of main magnets, rf upgrade and improvement of injection and extraction devices. The possibility of the beam power beyond 750 kW is being explored with new settings of the betatron tune.

Slides MOAM6P60 [9.968 MB]

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MOPM4P01

Challenges and Performance of the C-ADS Injector System

rfq, linac, proton, cavity

36

Y.L. Chi
IHEP, Beijing, People's Republic of China

Along with the rapid development of nuclear power plants in China, treatment of the nuclear waste has become a crucial issue. Supported by the "Strategic Priority Research Program" of the Chinese Academy of Sciences (CAS), The Chinese ADS project is now on-going based on the collaboration of several Chinese institutions. In the end of year 2015, China Initiative ADS (CIADS) program is approved by Chinese government, will construct in the Guangdong province south part of China. The proton accelerator of Chinese ADS is a superconducting CW linear accelerator. Its energy is 1.5GeV, with beam current of 10mA. Institute of High Energy Physics (IHEP) and Institute of Modern Physics (IMP) are responsible to developing this superconducting CW linear accelerator. In the injector part there are many challenges to developing several different low beta superconducting cavities and related hardware’s such like LLRF system etc. In this paper presents the progress of two different injector development including SC cavities and related hardware’s and performance test of two injectors and key hardware’s, and also brief introduction of CIADS program.

Slides MOPM4P01 [3.751 MB]

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MOPL016

Effects of Energy Deposition Models and Conductive Cooling on Wire Scanner Thermal Load, Analytical and Finite Element Analysis Approach

radiation, linac, simulation, insertion

221

B. Cheymol
ESS, Lund, Sweden

One of the main limitations of the wire scanner in high intensity linac is the inability of the wire to survive at high duty cycle. For the commissioning of such machines, duty cycle must be reduced to preserve interceptive devices. A good thermal model of the wire is needed to insure a safe operation of the wire scanner and set the limits of acceptable beam duty cycle. In this paper, we will discuss the influence of the energy deposition model and the efficiency of conductive cooling on the wire temperature, based on the ESS beam parameters.

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TUAM4X01

Electron Cloud in the CERN Accelerator Complex

emittance, electron, simulation, quadrupole

266

G. Rumolo, H. Bartosik, E. Belli, G. Iadarola, K.S.B. Li, L. Mether, A. Romano
CERN, Geneva, Switzerland
M. Schenk
EPFL, Lausanne, Switzerland

Operation with closely spaced bunched beams causes the build up of an Electron Cloud (EC) in both the LHC and the two last synchrotrons of its injector chain (PS and SPS). Pressure rise and beam instabilities are observed at the PS during the last stage of preparation of the LHC beams. The SPS was affected by coherent and incoherent emittance growth along the LHC bunch train over many years, before scrubbing has finally suppressed the EC in a large fraction of the machine. When the LHC started regular operation with 50 ns beams in 2011, EC phenomena appeared in the arcs during the early phases, and in the interaction regions with two beams all along the run. Operation with 25 ns beams (late 2012 and 2015), which is nominal for LHC, has been hampered by EC induced high heat load in the cold arcs, bunch dependent emittance growth and degraded beam lifetime. Dedicated and parasitic machine scrubbing is presently the weapon used at the LHC to combat EC in this mode of operation. This talk summarises the EC experience in the CERN machines (PS, SPS, LHC) and highlight the dangers for future operation with more intense beams as well as the strategies to mitigate or suppress the effect.

Slides TUAM4X01 [9.785 MB]

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TUPM1X01

Broadband Feedback System for Instability Damping in the SNS Ring

feedback, betatron, accumulation, extraction

288

N.J. Evans
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
The transverse feedback system in the Accumulator Ring of the Spallation Neutron Source~(SNS) is intended to damp broadband (≈40-120~MHz), coherent betatron motion due to e-p interaction. The SNS feedback system is based on an analog delay-line model with some signal conditioning and tuning parameters implemented digitally. This system provides a simple setup with two primary knobs, phase and gain, as well as an equalizer. This simplicity comes at the cost of some flexibility normally found in a standard mode-by-mode design, namely mode-by-mode phase, and gain control. In this paper we discuss the design, tuning, evaluation, and operation of the SNS feedback damper, and discuss the tradeoffs implicit in the design of the system.

Slides TUPM1X01 [2.352 MB]

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TUPM7X01

An Experimental Plan for 400 MeV H⁻ Stripping to Proton by Using Only Lasers in the J-PARC RCS

laser, proton, experiment, injection

310

P.K. Saha, H. Harada, S. Kato, M. Kinsho
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie, I. Yamane
KEK, Ibaraki, Japan

The 3-GeV RCS (Rapid Cycling Synchrotron) of J-PARC is gradually approaching to the design operation with 1 MW beam power. Studies are ongoing for further higher beam power of 1.5 MW. The injection and extraction energy of RCS is 0.4 and 3 GeV, respectively. Lifetime of the stripper foil is the highest concern beyond 1 MW beam power. We have also already started detail studies of H⁻ stripping to protons by using lasers. However, in order to avoid high magnetic field required in the process of laser-assisted H⁻ stripping to protons, especially for lower H⁻ energies, we are studying the possibilities of using only laser system for 400 MeV H⁻ beam in the RCS. The method is a three step process, similar to that of SNS but lasers are used instead of high field magnets in the 1st (H⁻ to H⁰) and 3rd step (H0* to p). A Nd:YAG laser can be properly used for both 1st and 3rd steps, where commercially available powerful Excimer laser will be used an H⁰ excitation in the 2nd step. Although detail R&D studies are necessary to reach to the ultimate goal, we plan to carry out an experiment in 2017. A detail of the present method, experimental schedule and the expected outcome will be presented.

Slides TUPM7X01 [3.316 MB]

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TUPM3Y01

Operational Experience and Future Plans at ISIS

injection, acceleration, proton, simulation

333

D.J. Adams
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
I.S.K. Gardner, B. Jones, A.H. Kershaw, A.P. Letchford, R.J. Mathieson, A. Pertica, B.G. Pine, A. Seville, H. V. Smith, C.M. Warsop, R.E. Williamson, M. Wright
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

The ISIS spallation neutron and muon source has been in operation since 1984. The accelerator complex consists of an H⁻ ion source, 665 keV RFQ, 70 MeV linac, 800 MeV proton synchrotron and associated beam transfer lines. The facility currently delivers ~2.8·10¹³ protons per pulse (ppp) at 50 Hz, which is shared between two target stations. High intensity performance and operation are dominated by the need to minimise and control beam loss, which is key to sustainable machine operation, allowing essential hands on maintenance. The facility has had several upgrades including an RFQ, ring Second Harmonic RF system, key developments of diagnostics and instrumentation required for improving beam control and a Second Target station. Upgrades being installed, or expected in the near future, include: a ring damping system, a new injector MEBT with fast injection chopper and an upgraded 50 Hz target. Operational experience of ISIS and the impacts of its past and future upgrades are discussed. Ideas for major upgrades to ISIS are briefly reviewed, as are the underlying R&D projects.

Slides TUPM3Y01 [2.902 MB]

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THAM1X01

Reuse Recycler: High Intensity Proton Stacking at Fermilab

proton, electron, booster, vacuum

463

P. Adamson
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
After a successful career as an antiproton storage and cooling ring, Recycler has been converted to a high intensity proton stacker for the Main Injector. We discuss the commissioning and operation of the Recycler in this new role, and the progress towards the 700 kW design goal.

Slides THAM1X01 [1.978 MB]

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THAM2X01

The Operation Experience at KOMAC

target, linac, DTL, ion

468

Y.-S. Cho, H.S. Kim, K. R. Kim, H.-J. Kwon, Y.G. Song
Korea Atomic Energy Research Institute (KAERI), Gyeongbuk, Republic of Korea
K.Y. Kim
KAERI, Daejon, Republic of Korea

Funding: This work was supported by the Ministry of Science, ICT & Future Planning of the Korean Government.
A 100-MeV proton linac at the KOMAC (Korea Multi-purpose Accelerator Complex) is composed of a 50-keV microwave ion source, a 3-MeV four-vane-type RFQ, a 100-MeV DTL and 10 target stations for proton irradiation on samples from many application fields. The linac was commissioned in 2013 and the user service started in July 2013 with delivering proton beam to two target stations: one for a 20-MeV beam and the other for a 100-MeV beam. In 2015, the linac has been operated more than 2,800 hours with an availability of greater than 89%. The unscheduled downtime was about 73 hours, mainly due to problems of ion source arcing and failures of pulsed high-voltage power system. More than 2,100 samples from various fields such as materials science, bio-life and nano technology and nuclear science, were treated in 2015. Currently, a new target station for radioisotope production is under commissioning and a new target station for low-flux irradiation experiments is being installed. Operational experiences of the 100-MeV linac during the past 3 years will be presented in the workshop.

Slides THAM2X01 [6.669 MB]

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THAM4X01

Investigation to Improve Efficiency and Availability in Control and Operation of Superconducting Cavity at ESS

cavity, klystron, LLRF, controls

474

R. Zeng
ESS, Lund, Sweden
O. Troeng
Lund University, Lund, Sweden

The higher efficiency and higher availability (fault-tolerant oriented) of RF&Cavity system (with beam loading) to operate at, the more dynamic details needs to be identified, so as to have the abilities (a) to work at nonlinearities, (b) to work close to limitation, and (c) to change operation point quickly and correctly. Dynamic detail identifications rely heavily on high precision measuring and characterizing basic cavity parameters (Ql, R/Q, dynamic detuning, phase and amplitude) and system behaviours under beam-RF-cavity interactions. It is especially challenging to characterize these dynamics under varying operating points or environment. Advanced technologies in LLRF and ICS providing real time/online characterizing will be the key enablers for addressing such challenges. However, to be successful, the deployment of these technologies must be embedded within local conditions taking into account available resources, existing hardware/software structures and operation modes. Several improvement approaches will be introduced. For example, 15% or more energy efficiency improvement at ESS will be obtained by reduction of power overhead and optimization of operation.

Slides THAM4X01 [2.165 MB]

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THAM4Y01

New Arrangement of Collimators of J-PARC Main Ring

collimation, beam-losses, proton, radiation

543

M.J. Shirakata, S. Igarashi, K. Ishii, Y. Sato, J. Takano
KEK, Ibaraki, Japan

The beam collimation system of J-PARC main ring has been prepared in order to localize the beam loss into the specified area, especially during the injection period. At the first time, it was constructed as a scraper-catcher system in horizontal and vertical planes which consisted of one halo-scraper and two scattered protons catchers, whose the maximum beam loss capacity was designed to be 450W in the beam injection straight of the ring. In 2012, the scraper was replaced by two collimators with a movable L-type jaw for both planes. Two catchers remained at the same places, and they were used as collimators. This large change of design concept of main ring collimation system was required in order to increase the beam loss capacity more than 3kW. The system worked well but unexpected loss spots still remained in the following arc and straight sections. The four-axis collimator was developed with movable jaw in horizontal, vertical and skew configurations which has high cleaning efficiency. We have four four-axis collimators, two non-skew collimators, and one original catcher. The most effective arrangement of collimators was investigated in this report.

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THAM5Y01

Path to Beam Loss Reduction in the SNS Linac Using Measurements, Simulation and Collimation

emittance, linac, optics, collimation

548

A.V. Aleksandrov, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
The SNS linac operation at its design average power currently is not limited by uncontrolled beam loss. However, further reduction of the beam loss remains an important aspect of the SNS linac tune up and operation. Even small “acceptable” beam loss leads to long term degradation of the accelerator equipment. The current state of model-based tuning at SNS leaves an unacceptably large residual beam loss level and has to be followed by an empirical, sometimes random, adjustment of many parameters to reduce the loss. This talk will discuss a set of coordinated efforts to develop tools for large dynamic range measurements, simulation and collimation in order to facilitate low loss linac tuning.

Slides THAM5Y01 [7.186 MB]

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